/*
* Routines to support checksumming of bytes.
*
* Copyright (C) 1996 Andrew Tridgell
* Copyright (C) 1996 Paul Mackerras
* Copyright (C) 2004-2018 Wayne Davison
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, visit the http://fsf.org website.
*/
#include "rsync.h"
extern int checksum_seed;
extern int protocol_version;
extern int proper_seed_order;
extern char *checksum_choice;
#define CSUM_NONE 0
#define CSUM_MD4_ARCHAIC 1
#define CSUM_MD4_BUSTED 2
#define CSUM_MD4_OLD 3
#define CSUM_MD4 4
#define CSUM_MD5 5
int xfersum_type = 0; /* used for the file transfer checksums */
int checksum_type = 0; /* used for the pre-transfer (--checksum) checksums */
/* Returns 1 if --whole-file must be enabled. */
int parse_checksum_choice(void)
{
char *cp = checksum_choice ? strchr(checksum_choice, ',') : NULL;
if (cp) {
xfersum_type = parse_csum_name(checksum_choice, cp - checksum_choice);
checksum_type = parse_csum_name(cp+1, -1);
} else
xfersum_type = checksum_type = parse_csum_name(checksum_choice, -1);
return xfersum_type == CSUM_NONE;
}
int parse_csum_name(const char *name, int len)
{
if (len < 0 && name)
len = strlen(name);
if (!name || (len == 4 && strncasecmp(name, "auto", 4) == 0)) {
if (protocol_version >= 30)
return CSUM_MD5;
if (protocol_version >= 27)
return CSUM_MD4_OLD;
if (protocol_version >= 21)
return CSUM_MD4_BUSTED;
return CSUM_MD4_ARCHAIC;
}
if (len == 3 && strncasecmp(name, "md4", 3) == 0)
return CSUM_MD4;
if (len == 3 && strncasecmp(name, "md5", 3) == 0)
return CSUM_MD5;
if (len == 4 && strncasecmp(name, "none", 4) == 0)
return CSUM_NONE;
rprintf(FERROR, "unknown checksum name: %s\n", name);
exit_cleanup(RERR_UNSUPPORTED);
}
int csum_len_for_type(int cst, BOOL flist_csum)
{
switch (cst) {
case CSUM_NONE:
return 1;
case CSUM_MD4_ARCHAIC:
/* The oldest checksum code is rather weird: the file-list code only sent
* 2-byte checksums, but all other checksums were full MD4 length. */
return flist_csum ? 2 : MD4_DIGEST_LEN;
case CSUM_MD4:
case CSUM_MD4_OLD:
case CSUM_MD4_BUSTED:
return MD4_DIGEST_LEN;
case CSUM_MD5:
return MD5_DIGEST_LEN;
default: /* paranoia to prevent missing case values */
exit_cleanup(RERR_UNSUPPORTED);
}
return 0;
}
int canonical_checksum(int csum_type)
{
return csum_type >= CSUM_MD4 ? 1 : 0;
}
/*
a simple 32 bit checksum that can be upadted from either end
(inspired by Mark Adler's Adler-32 checksum)
*/
uint32 get_checksum1(char *buf1, int32 len)
{
int32 i;
uint32 s1, s2;
schar *buf = (schar *)buf1;
s1 = s2 = 0;
for (i = 0; i < (len-4); i+=4) {
s2 += 4*(s1 + buf[i]) + 3*buf[i+1] + 2*buf[i+2] + buf[i+3] +
10*CHAR_OFFSET;
s1 += (buf[i+0] + buf[i+1] + buf[i+2] + buf[i+3] + 4*CHAR_OFFSET);
}
for (; i < len; i++) {
s1 += (buf[i]+CHAR_OFFSET); s2 += s1;
}
return (s1 & 0xffff) + (s2 << 16);
}
void get_checksum2(char *buf, int32 len, char *sum)
{
md_context m;
switch (xfersum_type) {
case CSUM_MD5: {
uchar seedbuf[4];
md5_begin(&m);
if (proper_seed_order) {
if (checksum_seed) {
SIVALu(seedbuf, 0, checksum_seed);
md5_update(&m, seedbuf, 4);
}
md5_update(&m, (uchar *)buf, len);
} else {
md5_update(&m, (uchar *)buf, len);
if (checksum_seed) {
SIVALu(seedbuf, 0, checksum_seed);
md5_update(&m, seedbuf, 4);
}
}
md5_result(&m, (uchar *)sum);
break;
}
case CSUM_MD4:
case CSUM_MD4_OLD:
case CSUM_MD4_BUSTED:
case CSUM_MD4_ARCHAIC: {
int32 i;
static char *buf1;
static int32 len1;
mdfour_begin(&m);
if (len > len1) {
if (buf1)
free(buf1);
buf1 = new_array(char, len+4);
len1 = len;
if (!buf1)
out_of_memory("get_checksum2");
}
memcpy(buf1, buf, len);
if (checksum_seed) {
SIVAL(buf1,len,checksum_seed);
len += 4;
}
for (i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK)
mdfour_update(&m, (uchar *)(buf1+i), CSUM_CHUNK);
/*
* Prior to version 27 an incorrect MD4 checksum was computed
* by failing to call mdfour_tail() for block sizes that
* are multiples of 64. This is fixed by calling mdfour_update()
* even when there are no more bytes.
*/
if (len - i > 0 || xfersum_type > CSUM_MD4_BUSTED)
mdfour_update(&m, (uchar *)(buf1+i), len-i);
mdfour_result(&m, (uchar *)sum);
break;
}
default: /* paranoia to prevent missing case values */
exit_cleanup(RERR_UNSUPPORTED);
}
}
void file_checksum(const char *fname, const STRUCT_STAT *st_p, char *sum)
{
struct map_struct *buf;
OFF_T i, len = st_p->st_size;
md_context m;
int32 remainder;
int fd;
memset(sum, 0, MAX_DIGEST_LEN);
fd = do_open(fname, O_RDONLY, 0);
if (fd == -1)
return;
buf = map_file(fd, len, MAX_MAP_SIZE, CSUM_CHUNK);
switch (checksum_type) {
case CSUM_MD5:
md5_begin(&m);
for (i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) {
md5_update(&m, (uchar *)map_ptr(buf, i, CSUM_CHUNK),
CSUM_CHUNK);
}
remainder = (int32)(len - i);
if (remainder > 0)
md5_update(&m, (uchar *)map_ptr(buf, i, remainder), remainder);
md5_result(&m, (uchar *)sum);
break;
case CSUM_MD4:
case CSUM_MD4_OLD:
case CSUM_MD4_BUSTED:
case CSUM_MD4_ARCHAIC:
mdfour_begin(&m);
for (i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) {
mdfour_update(&m, (uchar *)map_ptr(buf, i, CSUM_CHUNK),
CSUM_CHUNK);
}
/* Prior to version 27 an incorrect MD4 checksum was computed
* by failing to call mdfour_tail() for block sizes that
* are multiples of 64. This is fixed by calling mdfour_update()
* even when there are no more bytes. */
remainder = (int32)(len - i);
if (remainder > 0 || checksum_type > CSUM_MD4_BUSTED)
mdfour_update(&m, (uchar *)map_ptr(buf, i, remainder), remainder);
mdfour_result(&m, (uchar *)sum);
break;
default:
rprintf(FERROR, "invalid checksum-choice for the --checksum option (%d)\n", checksum_type);
exit_cleanup(RERR_UNSUPPORTED);
}
close(fd);
unmap_file(buf);
}
static int32 sumresidue;
static md_context md;
static int cursum_type;
void sum_init(int csum_type, int seed)
{
char s[4];
if (csum_type < 0)
csum_type = parse_csum_name(NULL, 0);
cursum_type = csum_type;
switch (csum_type) {
case CSUM_MD5:
md5_begin(&md);
break;
case CSUM_MD4:
mdfour_begin(&md);
sumresidue = 0;
break;
case CSUM_MD4_OLD:
case CSUM_MD4_BUSTED:
case CSUM_MD4_ARCHAIC:
mdfour_begin(&md);
sumresidue = 0;
SIVAL(s, 0, seed);
sum_update(s, 4);
break;
case CSUM_NONE:
break;
default: /* paranoia to prevent missing case values */
exit_cleanup(RERR_UNSUPPORTED);
}
}
/**
* Feed data into an MD4 accumulator, md. The results may be
* retrieved using sum_end(). md is used for different purposes at
* different points during execution.
*
* @todo Perhaps get rid of md and just pass in the address each time.
* Very slightly clearer and slower.
**/
void sum_update(const char *p, int32 len)
{
switch (cursum_type) {
case CSUM_MD5:
md5_update(&md, (uchar *)p, len);
break;
case CSUM_MD4:
case CSUM_MD4_OLD:
case CSUM_MD4_BUSTED:
case CSUM_MD4_ARCHAIC:
if (len + sumresidue < CSUM_CHUNK) {
memcpy(md.buffer + sumresidue, p, len);
sumresidue += len;
break;
}
if (sumresidue) {
int32 i = CSUM_CHUNK - sumresidue;
memcpy(md.buffer + sumresidue, p, i);
mdfour_update(&md, (uchar *)md.buffer, CSUM_CHUNK);
len -= i;
p += i;
}
while (len >= CSUM_CHUNK) {
mdfour_update(&md, (uchar *)p, CSUM_CHUNK);
len -= CSUM_CHUNK;
p += CSUM_CHUNK;
}
sumresidue = len;
if (sumresidue)
memcpy(md.buffer, p, sumresidue);
break;
case CSUM_NONE:
break;
default: /* paranoia to prevent missing case values */
exit_cleanup(RERR_UNSUPPORTED);
}
}
/* NOTE: all the callers of sum_end() pass in a pointer to a buffer that is
* MAX_DIGEST_LEN in size, so even if the csum-len is shorter that that (i.e.
* CSUM_MD4_ARCHAIC), we don't have to worry about limiting the data we write
* into the "sum" buffer. */
int sum_end(char *sum)
{
switch (cursum_type) {
case CSUM_MD5:
md5_result(&md, (uchar *)sum);
break;
case CSUM_MD4:
case CSUM_MD4_OLD:
mdfour_update(&md, (uchar *)md.buffer, sumresidue);
mdfour_result(&md, (uchar *)sum);
break;
case CSUM_MD4_BUSTED:
case CSUM_MD4_ARCHAIC:
if (sumresidue)
mdfour_update(&md, (uchar *)md.buffer, sumresidue);
mdfour_result(&md, (uchar *)sum);
break;
case CSUM_NONE:
*sum = '\0';
break;
default: /* paranoia to prevent missing case values */
exit_cleanup(RERR_UNSUPPORTED);
}
return csum_len_for_type(cursum_type, 0);
}